Natural fibers today are a popular choice for applications in composite manufacturing. Based on the sustainability benefits, biofibers such as plant fibers are replacing synthetic fibers in composites. These fibers are used to manufacture several biocomposites. The chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers. The reinforcement potential of natural fibers and their properties have been described in numerous papers. Today, high performance biocomposites are produced from several years of research. Plant fibers, particularly bast and leaf, find applications in automotive industries. While most of the other fibers are explored in lab scales they have not yet found large-scale commercial applications. It is necessary to also consider other fibers such as ones made from seed (coir) and animals (chicken feather) as they are secondary or made from waste products. Few plant fibers such as bast fibers are often reviewed briefly but other p...

A Review of Natural Fibers Used in Biocomposites: Plant, Animal and Regenerated Cellulose Fibers

The product. Coconut water (Cocos nucifera L.) is an ancien t tropical beverage whose popularity on the international market has been continuously increasing in recent years. Uses. Besides its various traditional uses, this refreshing liqu id extracted from the coconut fruit has recently been described as a "sport beverage" and has drawn the attention of manufacturers as a natural functional drink. Composition. Coconut water has a low matter content (2% to 5% wet basis), mainly comprising sugars and minerals. Quality criteria, such as the water per nut ratio, Total Soluble Solids (TSS), total sugar per nut, and [reducing sugars / total sugars] ratio, are good indicators for estimating the suitability of coconut cultivars for the production of coconut water. Regarding these criteria, dwarf varieties are the most suitable cultivars to obtain a tasty product. Properties. The quality of coconut water can not only be attributed to sugars and minerals because it also has a typical flavour and some original properties. Although many authors have cited medicinal uses or growth-promoting activities, only a few publications have clearly identified the components responsible for these properties. Discussion. Results of former and recent investigations are discussed. Finally, suggestions are made for further research to increase our knowledge of this original tropical juice. (Resume d'auteur)

/pdf/coconut-water-uses-composition-and-properties-a-review-1zvewkb9zf.pdf

Coconut water uses, composition and properties: a review

Objetivando-se estudar a qualidade da agua de irrigacao, em especial do aquifero situado no calcario da formacao Jandaira, na regiao produtora de melao localizada na Chapada do Apodi, realizou-se este trabalho utilizando-se resultados de 45 analises completas (CEa, pH e concentracoes de Na+, Ca2+, Mg2+, K+, Cl-, HCO3- e CO32-) de amostras dagua de diversas localidades, inseridas nos municipios de Mossoro e Barauna, e circunvizinhos, coletadas no periodo seco. As aguas dos pocos tubulares usadas para irrigacao apresentaram niveis elevados de salinidade, CEa variando de 1,25 a 3,00 dS m-1. Existem diferentes regioes, cada uma com valores de salinidade, composicao da agua e riscos de obstrucao especificos e diferenciados. Em algumas areas, a salinidade e a toxicidade do cloreto podem afetar, de forma significativa, o rendimento de culturas sensiveis. As aguas apresentam baixa sodicidade e elevada alcalinidade.

/pdf/caracterizacao-das-aguas-subterraneas-usadas-para-irrigacao-2ngjbbdbm7.pdf

Caracterização das águas subterrâneas usadas para irrigação na área produtora de melão da Chapada do Apodi

The Brazilian Cerrado is recognized as one of the most threatened biomes in the world, as the region has experienced a striking change from natural Cerrado vegetation to intense cash crop production. This paper reviews the history of land conversion in the Cerrado and the development of soil properties and water resources under past and ongoing land use. We compared soil and water quality parameters from different land uses considering 80 soil and 18 water studies conducted in different regions across the Cerrado to provide quantitative evidence of soil and water alterations from land use change.
 Following the conversion of native Cerrado, significant effects on soil pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the sites classified as croplands were nitrogen-fixing soybeans, which are not artificially fertilized with N. In contrast, water quality studies showed nitrogen enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and European Union (EU) water quality limits, which were potentially accompanied by serious health implications. Land use intensification is likely to continue, particularly in regions where less annual rainfall and severe droughts are projected in the northeastern and western Cerrado. Thus, the leaching risk and displacement of agrochemicals are expected to increase, particularly because the current legislation has caused a reduction in riparian vegetation. We conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This study may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado. Copyright (C) 2014 John Wiley & Sons, Ltd.

The Brazilian Cerrado: assessment of water and soil degradation in catchments under intensive agricultural use: ECOHYDROLOGICAL ASSESSMENT OF THE BRAZILIAN CERRADO

The objective of this study was to obtain and to numerical models to estimate the leaf area in function leaves linear dimension in sunflower. Two experiments were conducted at the experimental area of the Plant Science Department of the Federal University of Santa Maria, Santa Maria, RS, Brazil. Plants of sunflower were collected starting 27 days after emergency (DAE). The disks method was used to determine the leaf area (LA). Leaves were dried in oven at 65°C until constant weight. Linear, quadratic, cubic and power models between leaf area and length or width, and the product (length * width), were fitted. Models that apresented coefficient of determination lower than 0.90 were not selected. The statistic used to evaluate the performance of the models was the root mean square error (RQME). Models that had the best fit were power, quadratic and cubic using blade width as the independent variable. Leaf area in sunflower can be estimated with the power model, which was the most accurate, with width of the leaf.

/pdf/modelos-de-determinacao-nao-destrutiva-da-area-foliar-em-3d3y23qdmy.pdf

Modelos de determinação não-destrutiva da área foliar em girassol

A B S T R A C T Soil compaction influences all stages of crop growth, but in many low yield sugarcane fields critical levels and effects of soil compaction are ignored. Therefore, identifying localization and intensity of compaction are very relevant for descompactation of soil. In this context, this study aimed to apply three criteria for delineating zones for soil compaction management: soil layer where first appear values of soil penetration resistance considered critical for sugarcane growth; cone index for 0-40 cm layer, and depth of occurrence of maximum soil penetration resistance. Sampling was carried out in a grid with 113 points spaced at 100 m, georeferenced by means of a Global Positioning System receiver. Soil penetration resistance in eight layers of 5 cm depth, cone index and depth of occurrence of maximum penetration resistance were determined from data gathered by an automatic measuring penetrometer. Estimative of non-sampled values were obtained by means of kriging interpolation, which allowed drawing of contour maps and the definition of four regions in the field for site specific subsoiling . Palavras-chave: Saccharum ssp. resistencia do solo a penetracao geoestatistica penetrometro

/pdf/revista-brasileira-de-engenharia-agricola-e-ambiental-gtuvs7hr7n.pdf

Revista Brasileira de Engenharia Agrícola e Ambiental

Objetivando-se determinar a variacao da composicao ionica de aguas do cristalino do Nordeste brasileiro, realizou-se este trabalho utilizando-se um banco de dados correspondente a 557 resultados de analises quimicas de agua de diversas fontes, com condutividade eletrica (CEa) ate 5.000 µS cm-1, pertencentes as diversas propriedades rurais situadas no cristalino dos Estados da Paraiba, Rio Grande do Norte e Ceara. Foi determinada a composicao ionica percentual das aguas, levando-se em conta o local de origem das amostras e o nivel de salinidade em que as mesmas se apresentavam; a partir dai, confeccionaram-se graficos quanto a composicao ionica e,para os teores de Na+, Cl-,Ca2+ + Mg2+ e RAS, obtiveram-se equacoes de regressao linear com a condutividade eletrica. Os resultados mostraram que, de modo geral, as aguas do cristalino do Nordeste brasileiro sao cloretadas sodicas com alguma variacao, de acordo com a litologia do local de origem e para fins de previsao, de regressoes elaboradas em base local foram melhores que global, com excecao de Ca2+ + Mg2+ para o Nucleo de Pau dos Ferros,RN.

/pdf/composicao-quimica-de-aguas-do-cristalino-do-nordeste-48yfk4h4c0.pdf

Composição química de águas do cristalino do nordeste brasileiro

The melon produced in the state of Rio Grande do Norte is cultivated under irrigation and fertigation. With the use of fertigation and knowledge of the nutrients uptake curves it is possible to divide the total dose of nutrients in several applications during the crop cycle. Thus, the objectives of this study were to obtain curves of dry matter accumulation and the uptake of nitrogen, phophorus, potassium, calcium and magnesium for the "pele-de-sapo" melon plants and to determine the total uptake of these nutrients at the end of the crop cycle. The experimental design was an entirely randomized blocks with three replications. Plants were sampled at 22, 33, 43, 54 and 69 days after the sowing and were determined the dry matter and plant contents of N, P, K, Ca and Mg. It was observed that: 1) more than 50% of the extracted nutrients were accumulated in the vegetative part of the plant; 2) potassium, calcium and nitrogen are the nutrients more demanded by the melon plant; 3) the period of larger demand of nutrients happened between 43 and 54 days after sowing; 4) leaves and fruits are the principal drains of nutrients in the whole cycle of the crop.

/pdf/acumulo-de-materia-seca-e-absorcao-de-nutrientes-pelo-369jsspgjn.pdf

Acúmulo de matéria seca e absorção de nutrientes pelo meloeiro "pele-de-sapo"

The leaf area of the Gold Mine melon was estimated when submitted to irrigation water levels varying from 55% to 130% of the hydric necessity of the crop, utilizing low and high salinity water. One plant per plot was collected at 19; 26; 34; 40 and 50 days after sowing, obtaining data of length, width, total leaf area, number of leaves, and individual leaf areas up to 24 leaves per plant. The results indicated that a partial correlation between the total plant leaf area (AF) and the number of leaves (NF) exists, with r2 = 0.95**, and the regression equation AF = 108NF - 516, with r2 = 0.95. The comparison of the models showed that at least one relation between leaf width (L) and leaf area (AF) differentiated from the others, even though the relation that assumes the whole data set (AF=0,826L1,89; r2 = 0.97) has a high determination coefficient.

/pdf/estimativa-da-area-foliar-do-meloeiro-1tvkkp665a.pdf

Estimativa da área foliar do meloeiro

Resumen pt: O uso de agua salina na irrigacao e muito comum em cultivos de melao em regioes semi-aridas, o que pode resultar na salinizacao do solo e na reducao de r...

/pdf/manejo-da-irrigacao-e-tolerancia-do-meloeiro-a-salinidade-da-4861cpdqvb.pdf

José Francismar de Medeiros

Papers

Revista Brasileira de Engenharia Agrícola e Ambiental

Composição química de águas do cristalino do nordeste brasileiro

Acúmulo de matéria seca e absorção de nutrientes pelo meloeiro "pele-de-sapo"

Estimativa da área foliar do meloeiro

Manejo da irrigação e tolerância do meloeiro a salinidade da água de irrigação